The present invention relates to new compounds, in particular to new asymmetric stilbene UV absorber compounds which are useful as sun protection agents; and to a method of improving the sun protection factor (SPF) of textile fibre material, especially cotton, polyamide and wool, comprising treating them with the new compounds.
It is known that light radiation of wavelengths 280-400 nm permits tanning of the epidermis. Also known is that rays of wavelengths 280-320 nm (termed UV-B radiation), cause erythemas and skin burning which can inhibit skin tanning.
Radiation of wavelengths 320-400 nm (termed UV-A radiation) is known to induce skin tanning but can also cause skin damage, especially to sensitive skin which is exposed to sunlight for long periods. Examples of such damage include loss of skin elasticity and the appearance of wrinkles, promotion of the onset of erythemal reaction and the inducement of phototoxic or photoallergic reactions.
Any effective protection of the skin from the damaging effects of undue exposure to sunlight clearly needs to include means for absorbing both UV-A and UV-B components of sunlight before they reach the skin surface.
Traditionally, protection of exposed human skin against potential damage by the UV components in sunlight has been effected by directly applying to the skin a preparation containing a UV absorber. In areas of the world, e.g. Australia and America, which enjoy especially sunny climates, there has been a great increase in the awareness of the potential hazards of undue exposure to sunlight, compounded by fears of the consequences of alleged damage to the ozone layer. Some of the more distressing embodiments of skin damage caused by excessive, unprotected exposure to sunlight are development of melanomas or carcinomas on the skin.
One aspect of the desire to increase the level of skin protection against sunlight has been the consideration of additional measures, over and above the direct protection of the skin. For example, consideration has been given to the provision of protection to skin covered by clothing and thus not directly exposed to sunlight.
Most natural and synthetic textile materials are at least partially permeable to UV components of sunlight. Accordingly, the mere wearing of clothing does not necessarily provide skin beneath the clothing with adequate protection against damage by UV radiation. Although clothing containing a deeply coloured dye and/or having a tight weave texture may provide a reasonable level of protection to skin beneath it, such clothing is not practical in hot sunny climates, from the standpoint of the personal comfort of the wearer.
There is a need, therefore, to provide protection against UV radiation for skin which lies underneath clothing, including lightweight summer clothing, which is undyed or dyed only in pale shades. Depending on the nature of the dyestuff, even skin beneath clothing dyed in some dark shades may also require protection from UV radiation.
Such lightweight summer clothing normally has a density of less than 200 g/m2 and has a sun protection factor rating between 1.5 and 20, depending on the type of fibre from which the clothing is manufactured.
The SPF rating of a sun protectant (sun cream or clothing) may be defined as the multiple of the time taken for the average person wearing the sun protectant to suffer sun burning under average exposure to sun. For example, if an average person would normally suffer sun burn after 30 minutes under standard exposure conditions, a sun protectant having an SPF rating of 5 would extend the period of protection from 30 minutes to 2 hours and 30 minutes. For people living in especially sunny climates, where mean sun burn times are minimal, e.g. only 15 minutes for an average fair-skinned person at the hottest time of the day, SPF ratings of at least 20 are desired for lightweight clothing.
It is already known, e.g. from WO 94/4515, that the application of specified types of UVA to a light-weight textile materials in general can effect an increase in the SPF value of the textile so treated. The increase in SPF value achieved thereby, however, is relatively modest.
The use of fluorescent whitening agents (FWAs) in order to effect an increase in the SPF value of textiles has also been proposed. Most FWAs, however, are only effective in absorbing radiation in the UV-A range. Certain symmetric FWAs have been disclosed in EP-A728,749 which absorb radiation in both the UV-A and UV-B ranges, and impart greatly increased SPF ratings to textile fibre materials treated with them.
In Chem.Abstracts, 1962, 12913a (Japan 14,728), there are described certain asymmetric FWAs, but these known compounds have no UV-B absorbing properties so that they are not able to impart useful SPF ratings to textile materials treated with them.
Certain new asymmetric stilbene UV absorber compounds have now been found which, relative to known symmetric stilbene UV absorber compounds, are easy to formulate and impart both excellent whiteness levels and SPF ratings to textile materials treated with them.
Accordingly, the present invention provides, as a first aspect, an asymmetric compound having the formula: 
in which M is hydrogen, an alkali metal atom, ammonium or a cation formed from an amine; Xa and Xb are the same or different and each is NH2; NH(C1-C4alkyl); N(C1-C4alkyl)2; NH(C2-C4alkoxyalkyl); N(CH2CH2OH)2; a group NHxe2x80x94Zxe2x80x94NR1R2 in which Z is C2-C14alkylene or optionally substituted arylene, and R1 and R2 are the same or different and each is C1-C12alkyl or R1 and R2, together with the nitrogen atom to which they are each attached, form a morpholino, piperidino or piperazino ring; an aminoacid residue; C1-C4alkoxy; hydroxy-substituted-C2-C4alkoxy; 
and
Ya and Yb are the same or different and each is a substituted amino group having both UVA and UVB-absorbing properties, preferably a group having the formula: 
in which R3 is CN; SO2R5 which R5 is, C1-C12alkyl, C1-C12alkoxy, NH2, NH(C1-C4alkyl), N(C1-C4alkyl)2, N(CH2CH2OH)2, C1-C4alkoxy or hydroxy-substituted-C2-C4alkoxy; COR5 in which R5 has its previous significance; COOM in which M has its previous significance or NHCOR5 in which R5 has its previous significance and
R4 has the same significance as R3 or is H, OH, C1-C4alkyl or C1-C4alkoxy; and one of Xa and Xb can be identical to one of Ya and Yb, provided that one of Xa and Xb is different from the other and/or one of Ya and Yb is different from the other.
Preferably, M is hydrogen, sodium, potassium, calcium, magnesium, ammonium, mono-, di-, tri- or tetra-C1-C4alkylammonium, mono-, di-, tri- or tetra-C1-C4hydroxyalkylammonium, or ammonium that is di- or tri-substituted with a mixture of C1-C4alkyl and C1-C4hydroxyalkyl groups. Preferably, each M is sodium.
When one or more of Xa, Xb and R5 are NH(C1-C4alkyl), examples of such groups are NH-ethyl, NH-n-propyl, NH-isopropyl, NH-n-butyl and, in particular, NH-methyl groups.
When one or more of Xa, and Xb are NH(C2-C4alkoxyalkyl), examples of such groups are ethoxyethyl, methoxypropyl and, in particular,methoxyethyl.
When one or more of Xa, Xb and R5 are N(C1-C4alkyl)2, examples of such groups are N(ethyl)2, N(n-propyl)2, N(isopropyl)2, N(n-butyl)2 and, in particular, N(methyl)2 groups.
When one or both of Xa and Xb is a group NHxe2x80x94Zxe2x80x94NR1R2, C2-C14alkylene groups Z include, e.g., ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,8-octylene, 1,10-decylene, 1,12-dodecylene and 1,14-tetradecylene groups. Preferred are C2-C6alkylene groups Z, most preferably the 1,3-propylene group. Optionally substituted arylene Z include the naphthylene and, preferably, the phenylene group. The optionally substituted arylene Z may be substituted, for example with one or more C1-C4alkyl groups. C1-C12alkyl groups R1 and R2 may be, e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl and n-dodecyl groups, preferably methyl or ethyl groups.
An aminoacid residue Xa and/or Xb may be, e.g., one having the formula xe2x80x94NHxe2x80x94CH(CO2H)-R6 in which R6 is hydrogen or a group having the formula CHR7R8 in which R7 and R8, independently, are hydrogen or C1-C4alkyl optionally substituted by one or two substituents selected from hydroxy, thio, methylthio, amino, carboxy, sulfo, phenyl, 4-hydroxyphenyl, 3,5-diiodo-4-hydroxyphenyl, xcex2-indolyl, xcex2-imidazolyl and NHxe2x95x90C(NH2)NHxe2x80x94.
Specific examples of aminoacids from which such preferred aminoacid residues Xa and/or Xb are derived include glycine, alanine, sarcosine, serine, cysteine, phenylalanine, tyrosine (4-hydroxyphenylalanine), diiodotyrosine, tryptophan (xcex2-indolylalanine), histidine ((xcex2-imidazolylalanine), xcex1-aminobutyric acid, methionine, valine (xcex1-aminoisovaleric acid), norvaline, leucine (xcex1-aminoisocaproic acid), isoleucine (xcex1-amino-xcex2-methylvaleric add), norleucine (xcex1-amino-n-caproic acid), arginine, omithine (xcex1xcex4-iaminovaleric acid), lysine (xcex1, xcex5-diaminocaproic acid), aspartic acid (aminosuccinic acid), glutamic acid (xcex1-aminoglutaric acid), threonine, hydroxyglutamic acid and taurine, as well as mixtures and optical isomers thereof. Of these aminoacids from which such preferred aminoacid residues Xa and/or Xb are derived, sarcosine, taurine, glutamic acid and aspartic acid are particularly preferred.
A further preferred example of an aminoacid from which an aminoacid residue Xa and/or Xb may be derived is iminodiacetic acid.
Other, less preferred examples of aminoacids from which aminoacid residues Xa and/or Xb may be derived include cystine, lanthionine, proline and hydroxyproline.
A C1-C4alkoxy residue Xa and/or Xb, R4 or R5 may be, e.g., ethoxy, n-propoxy, isopropoxy, n-butoxy or, especially, methoxy residue.
An hydroxy-substituted-C2-C4alkoxy group Xa and/or Xb or R5 may be, e.g., 2-hydroxyethoxy, 3-hydroxypropoxy or 4-hydroxybutoxy group.
A C1-C4alkyl group R4 may be, e.g., ethyl, n-propyl, isopropyl, n-butyl or, especially, methyl group.
Preferred asymmetric compounds of formula (1) are those in which Xa and Xb are the same and Ya and Yb are different; and those in which Ya and Yb are the same and Xa and Xb are different.
In the groups Ya and Yb of formula (2), preferably the substituents R3 and R4 are in the 2- and 4-positions relative to the NH substituent.
Preferably, in the groups Ya and Yb of formula (2), R3 is CN; SO2R5 in which R5 is, C1-C12alkyl, C1-C12alkoxy, NH2, NH(C1-C4alkyl), N(C1-C4alkyl)2, N(CH2CH2OH)2, C1-C4alkoxy or hydroxy-substituted-C2-C4alkoxy; COR5 in which R5 has its previous significance; COOM in which M has its previous significance or NHCOR5 in which R5 has its previous significance and in R4 is hydrogen.
The asymmetric compounds of formula (1) may be produced by reacting, under known reaction conditions, cyanuric chloride, successively, in any desired sequence, with each of an aminostilbene-sulfonic acid, an amino compound capable of introducing a group Xa and Xb in which Xa and Xb have their previous significance, and a compound capable of introducing a group Ya and Yb in which Ya and Yb have their previous significance, provided that one of Xa and Xb is different from the other and/or one of Ya and Yb is different from the other. Alternatively, the asymmetric compounds of formula (1) can be obtained as a mixture with the analogous symmetric compounds by reacting, in one pot, cyanuric chloride, an aminostilbene-sulfonic acid, and the respective stoichiometric amounts of an amino compound capable of introducing a group Xa and Xb, in which Xa and Xb have their previous significance, and a compound capable of introducing a group Ya and Yb, in which Ya and Yb have their previous significance.
The starting materials are known compounds which are readily available.
Especially preferred asymmetric compounds of formula (1) are those obtained in the form of a mixture with the analogous symmetric compounds by reacting, in one pot, the respective stoichiometric amounts of cyanuric chloride, each of an aminostilbene-sulfonic acid, an amino compound capable of introducing a group Xa and Xb, in which Xa and Xb have their previous significance, and a compound capable of introducing a group Ya and Yb, in which Ya and Yb have their previous significance. For example, if Ya and Yb are the same and Xa and Xb are different, in this way, there is obtained a mixture of the following compounds: 
The present invention also provides, as a second aspect, a method for the improvement of the SPF of a textile fibre material, comprising treating the textile fibre material with 0.05 to 3.0% by weight, based on the weight of the textile fibre material, of one or more compounds having the formula (1).
The textile fibres treated according to the method of the present invention may be natural or synthetic fibres or mixtures thereof. Examples of natural fibres include vegetable fibres such as cotton, viscose, flax, rayon or linen, preferably cotton and animal fibres such as wool, mohair, cashmere, angora and silk, preferably wool. Synthetic fibres include polyester, polyamide and polyacrylonitrile fibres. Preferred textile fibres are cotton, polyamide and wool fibres.
Preferably, textile fibres treated according to the method of the present invention have a density of less than 200 g/m2 and have not been previously dyed in deep shades.
Some of the compounds of formula (1) used in the method of the present invention may be only sparingly soluble in water and may need to be applied in dispersed form. For this purpose, they may be milled with an appropriate dispersant, conveniently using quartz balls and an impeller, down to a particle size of 1-2 microns.
As dispersing agents for such sparingly-soluble compounds of formula (1) there may be mentioned:
acid esters or their salts of alkylene oxide adducts, e.g., acid esters or their salts of a polyadduct of 4 to 40 moles of ethylene oxide with 1 mole of a phenol, or phosphoric acid esters of the adduct of 6 to 30 moles of ethylene oxide with 1 mole of 4-nonylphenol, 1 mole of dinonylphenol or, especially, with 1 mole of compounds which have been produced by the addition of 1 to 3 moles of styrenes on to 1 mole of phenol;
polystyrene sulphonates;
fatty acid taurides;
alkylated diphenyloxide-mono- or -di-sulphonates;
sulphonates of polycarboxylic acid esters;
addition products of 1 to 60, preferably 2 to 30 moles of ethylene oxide and/or propylene oxide on to fatty amines, fatty amides, fatty acids or fatty alcohols, each having 8 to 22 carbon atoms, or on to tri- to hexavalent C3-C6alkanols, the addition products having been converted into an acid ester with an organic dicarboxylic acid or with an inorganic polybasic acid;
lignin sulphonates; and, in particular
formaldehyde condensation products, e.g., condensation products of lignin sulphonates
and/or phenol and formaldehyde; condensation products of formaldehyde with aromatic sulphonic acids, e.g., condensation products of ditolylethersulphonates and formaldehyde; condensation products of naphthalenesulphonic acid and/or naphthol- or
naphthylaminesulphonic acids and formaldehyde; condensation products of phenolsulphonic acids and/or sulphonated dihydroxydiphenylsulphone and phenols or cresols with formaldehyde and/or urea; or condensation products of diphenyloxide-disulphonic acid derivatives with formaldehyde.
Depending on the type of compound of formula (1) used, it may be beneficial to carry out the treatment in a neutral, alkaline or acidic bath. The method is usually conducted in the temperature range of from 20 to 140xc2x0 C., for example at or near to the boiling point of the aqueous bath, e.g. at about 90xc2x0 C.
Solutions of the compound of formula (1), or its emulsions in organic solvents may also be used in the method of the present invention. For example, the so-called solvent dyeing (pad thermofix application) or exhaust dyeing methods in dyeing machines may be used.
If the method of the present invention is combined with a textile treatment or finishing method, such combined treatment may be advantageously carried out using appropriate stable preparations which contain the compound of formula (1) in a concentration such that the desired SPF improvement is achieved.
In certain cases, the compound of formula (1) is made fully effective by an after-treatment. This may comprise a chemical treatment such as treatment with an acid, a thermal treatment or a combined thermal/chemical treatment.
It is often advantageous to use the compound of formula (1) in admixture with an assistant or extender such as anhydrous sodium sulfate, sodium sulfate decahydrate, sodium chloride, sodium carbonate, an alkali metal phosphate such as sodium or potassium orthophosphate, sodium or potassium pyrophosphate or sodium or potassium tripolyphosphate, or an alkali metal silicate such as sodium silicate.
In addition to the compounds of formula (1), a minor proportion of one or more adjuvants may also be employed in the method of the present invention. Examples of adjuvants include emulsifiers, perfumes, colouring dyes, opacifiers, further fluorescent whitening agents, bactericides, nonionic surfactants, fabric care ingredients, especially fabric softeners, stain release or stain repellant ingredients or water-proofing agents, anti-gelling agents such as nitrites or nitrates of alkali metals, especially sodium nitrate, and corrosion inhibitors such as sodium silicate.
The amount of each of these optional adjuvants should not exceed 1%, and preferably ranges from 0.01 to 1% by weight on the treated fibre.
The method of the present invention, in addition to providing protection to the skin, also increases the useful life of a textile article treated according to the present invention. In particular, the tear resistance and/or lightfastness of the treated textile fibre material may be improved.
The present invention also provides a textile fabric produced from a fibre treated according to the method of the present invention as well as an article of clothing produced from the said fabric.
Such textile fabrics and articles of clothing produced from the said fabrics typically have an SPF rating of 20 and above whereas untreated cotton, for example, generally has an SPF rating of from 2 to 4.
The treatment method according to the present invention may also be conducted by washing the textile fibre material with a detergent containing at least one compound of formula (1), thereby imparting an excellent sun protection factor to the fibre material so washed.
The detergent treatment according to the present invention is preferably effected by washing the textile fibre material at least once with the detergent composition at a temperature ranging from 10 to 100xc2x0 C., especially from 15 to 60xc2x0 C.
The detergent composition used preferably comprises:
i) 5-90%, preferably 5-70% of an anionic surfactant and/or a nonionic surfactant;
ii) 5-70%, preferably 5-40% of a builder;
iii) 0-30%, preferably 1-12% of a peroxide;
iv) 0-10%, preferably 1-6% of a peroxide activator and/or 0-1%, preferably 0.1-0.3% of a bleaching catalyst;
v) 0.005-2%, preferably 0.01-1% of at least one compound of formula (1); and
vi) 0.005-10%, preferably 0.1-5% of of one or more auxiliaries, each by weight, based on the total weight of the detergent.
The said detergent compositions are also new and, as such form a further aspect of the present invention.
The detergent may be formulated as a solid, as an aqueous liquid comprising 5-50, preferably 10-35% water or as a non-aqueous liquid detergent, containing not more than 5, preferably 0-1 wt. % of water, and based on a suspension of a builder in a non-ionic surfactant, as described, e.g., in GB-A-2158454.
The anionic surfactant component may be, e.g., a sulphate, sulphonate or carboxylate surfactant, or a mixture of these.
Preferred sulphates are alkyl sulphates having 12-22 carbon atoms in the alkyl radical, optionally in combination with alkyl ethoxy sulphates having 10-20 carbon atoms in the alkyl radical.
Preferred sulphonates include alkyl benzene sulphonates having 9-15 carbon atoms in the alkyl radical.
In each case, the cation is preferably an alkali metal, especially sodium.
Preferred carboxylates are alkali metal sarcosinates of formula Rxe2x80x94CO(R1)CH2COOM1 in which R is alkyl or alkenyl having 9-17 carbon atoms in the alkyl or alkenyl radical, R1 is C1-C4 alkyl and M1 is alkali metal.
The nonionic surfactant component may be, e.g., a condensate of ethylene oxide with a C9-C15 primary alcohol having 3-8 moles of ethylene oxide per mole.
The builder component may be an alkali metal phosphate, especially a tripolyphosphate; a carbonate or bicarbonate, especially the sodium salts thereof; a silicate or disilicate; an aluminosilicate; a polycarboxylate; a polycarboxylic acid; an organic phosphonate; or an aminoalkylene poly(alkylene phosphonate); or a mixture of these.
Preferred silicates are crystalline layered sodium silicates of the formula NaHSimO2m+1.pH2O or Na2SimO2m+1.pH2O in which m is a number from 1.9 to 4 and p is 0 to 20.
Preferred aluminosilicates are the commercially-available synthetic materials designated as Zeolites A, B, X, and HS, or mixtures of these. Zeolite A is preferred.
Preferred polycarboxylates include hydroxypolycarboxylates, in particular citrates, polyacrylates and their copolymers with maleic anhydride.
Preferred polycarboxylic acids include nitrilotriacetic acid and ethylene diamine tetra-acetic acid.
Preferred organic phosphonates or aminoalkylene poly(alkylene phosphonates) are alkali metal ethane 1-hydroxy diphosphonates, nitrilo trimethylene phosphonates, ethylene diamine tetra methylene phosphonates and diethylene triamine penta methylene phosphonates.
Any peroxide component may be any organic or inorganic peroxide compound, described in the literature or available on the market, which bleaches textiles at conventional washing temperatures, e.g. temperatures in the range of from 5xc2x0 C. to 90xc2x0 C. In particular, the organic peroxides are, for example, monoperoxides or polyperoxides having alkyl chains of at least 3, preferably 6 to 20, carbon atoms; in particular diperoxydicarboxylates having 6 to 12 C atoms, such as diperoxyperazelates, diperoxypersebacates, diperoxyphthalates and/or diperoxydodecanedioates, especially their corresponding free acids, are of interest. It is preferred, however, to employ very active inorganic peroxides, such as persulphate, perborate and/or percarbonate. It is, of course, also possible to employ mixtures of organic and/or inorganic peroxides. The peroxides, especially the inorganic peroxides, are preferably activated by the inclusion of an activator such as tetraacetyl ethylenediamine or nonoyloxybenzene sulfonate. Bleaching catalysts which may be added indude, e.g., enzymatic peroxide precursors and/or metal complexes. Preferred metal complexes are manganese or iron complexes such as manganese or iron phthalocyanines or the complexes described in EP-A0509787.
The detergents used will usually contain one or more auxiliaries such as soil suspending agents, for example sodium carboxymethylcellulose; salts for adjusting the pH, for example alkali or alkaline earth metal silicates; foam regulators, for example soap; salts for adjusting the spray drying and granulating properties, for example sodium sulphate; perfumes; and also, if appropriate, antistatic and softening agents; such as smectite clays; enzymes, such as amylases and proteases; photobleaching agents; pigments; and/or shading agents. These constituents should, of course, be stable to any bleaching system employed.
Compounds of the formula (I) have also been found to be useful for the fluorescent whitening of textile materials, in which connection polyamides, wool and cotton should be singled out particularly, and of paper.
The asymmetric compounds of formula (1) offer several advantages with respect to their symmetric analogues: since more substituents are present in the molecule, the applicational properties of the corresponding symmetric analogues can be combined, or even improved; the asymmetric compounds of formula (1) dissolve in water more rapidly and to a greater extent than the corresponding symmetric analogues; and, since the colour shade and affinity are dependent on the substituent type, the fact that asymmetric compounds of formula (1) contain three different substituents gives more scope for modifying each of these important properties.